The present invention relates to a method for automatically adjusting a value of an electronic part such as a coil, a resistor and a trimmer capacitor mounted on a printed circuit board.
It is preferable that the electronic part on the printed circuit board is automatically adjusted to a proper value in dependency on an operation of a circuit.
In the automatic adjustment, an output signal at a measuring point of the printed circuit board is measured when operating, and an adjusting member of the electronic part is rotated with a screw driver until the output signal becomes a desired value.
FIG. 6 shows a flowchart of an operation for an adjusting method of a conventional automatic adjusting system. The output signal of the circuit is measured at a step 101. The adjusting member of the electronic part is rotated at a step 102. The output signal is measured at a step 103. A deviation of the output signal from the desired value is calculated at a step 104. At a step 105, it is determined whether the deviation becomes zero or not. If not, the program returns to the step 102. The rotation of the adjusting member is adjusted in dependency on the deviation until the deviation becomes zero at the step 105.
FIG. 7 shows the relationship between the output signal and the rotating angle of the adjusting member in the operation of the flowchart.
FIG. 8 shows an adjusting method of another conventional adjusting system. The output signals are measured at a step 301. A function representing the relationship between the adjustment quantity and the output signal is experimentally or logically obtained. In order to obtain the function, since output signals at a plurality of measuring points must be measured, a long time will be required to obtain the function. Therefore it is determined whether the function is complicated at a step 302. If not, the adjustment quantity is calculated at a step 303 with the function. The adjusting member is rotated in accordance with the calculated adjusting quantity at a step 304, and the program is terminated. If the function is complicated at the step 302, the program proceeds to a step 305 where a data which is previously calculated and stored in a memory is derived from the memory. The program goes to the step 304.
FIG. 9 shows a characteristic between the output signal and the rotating angle of the adjusting member.
FIG. 10 shows an operation of a driving control section provided in the system of FIG. 6. In the section, the adjusting member is rotated (step 501) until a stop command is produced (step 502).
FIG. 11 shows an operation of a measuring control section provided in the system of FIG. 6. In the section, the output signal is measured (step 601) until the desired value is obtained (step 602). When the desired value is obtained, the stop command is set (step 603).
FIG. 12 shows a characteristic between the output signal and the rotating angle in dependency on the operations of FIGS. 10 and 11.
In the former method, the number of samplings for measuring the output signal is large, so that it takes a long time to accomplish the adjustment.
Also in the latter method, a long time is required to measure output signals at a plurality of points. A part having a different shape can not be adjusted by the method. The method can not respond to a non-linear response characteristic. Furthermore, it is necessary to provide a separating process for inspecting an adjusting range.